unknown if this is attenuated by increasing calcium or vitamin D intake (S. S. Harris et al., 2001; Cauley et al., 2005b; Tracy et al., 2005). There is limited information on the effect of calcium and vitamin D supplements on bone mass or fracture in older subjects, because African Americans have usually not been included in clinical trials in meaningful numbers. A 3-year randomized, double-blind, placebo-controlled vitamin D3 intervention in postmenopausal black women showed no difference in rate of bone loss between treatment and control groups (Aloia et al., 2005). There was also no relationship between serum 25OHD and rates of bone loss. The WHI did include African American subjects, who took part in a calcium plus vitamin D trial. Hip fracture risk was not reduced by the intervention (Jackson et al., 2006). Changes in bone density in this trial were adjusted for race, but separate analyses by race for the positive outcome on BMD of the hip were not provided. However, a more recent meeting presentation using data from the WHI Observational Study (Cauley et al., 2009) has revealed the concerning finding that fracture risk was directly related to serum 25OHD level in the African American subgroup.

Thus, although the available, emerging evidence would suggest that there is perhaps a lower requirement for calcium and vitamin D among African Americans relative to ensuring bone health, at least compared with whites, there is a notable lack of high-quality and convincing evidence to act on this possibility or to set different requirements for persons of African American ancestry. See Chapter 6 for discussions related to race/ethnicity and estimation of the Tolerable Upper Intake Levels (ULs) for vitamin D.

SELECTION OF INDICATORS

As described in Chapter 1, following the examination of the relevance and quality of the data for the potential indicators of interest, the next step in the DRI development process is to select the indicator or indicators to be used for estimating average requirements or EARs, in this case for calcium and vitamin D. Overall, the selection of indicators is evidence-based; indicators for levels of dietary adequacy are selected based on the strength and quality of the evidence and their demonstrated public health significance, taking into consideration sources of uncertainty in the evidence.

The indicator of bone health is selected as to form the basis of the DRIs for calcium and vitamin D for all life stage groups. With the exception of measures related to bone health, the potential indicators examined are currently not associated with evidence that could be judged either compelling or sufficient in terms of cause and effect, nor informative regarding dose–response relationships for the purposes of determining nutrient requirements. Cancer/neoplasms, cardiovascular disease and hypertension, diabetes and metabolic syndrome, falls and physical performance, im-